Nick Clegg was forced to issue an embarrassing clarification tonight after suggesting that official predictions existed for how many Romanians and Bulgarians could come to Britain.

The Deputy Prime Minister said he had "seen estimates" of immigration after restrictions on the EU countries are lifted at the end of this year.

He also appeared to indicate that figures would be made public if they became "precise enough".

Mr Clegg's comments - in response to a caller on his weekly LBC 97.3 radio phone-in - reignited speculation that was originally sparked by Communities Secretary Eric Pickles last month.

The Tory minister claimed to have seen official forecasts, but refused to give details because he did not have confidence in them.

Downing Street and the Home Office have since insisted that no such information has been produced, and there would be no point doing so because it could not be reliable.

Mr Clegg this morning attacked the Labour government for "bandying about" figures on immigration from Poland and the Czech Republic that turned out to be completely wrong.

He said the coalition was not going to "pretend that we have scientific figures" for Romania and Bulgaria, but added: "We've seen estimates but they are estimates, I don't think it helps public confidence in the immigration system if we start...

"I don't think we as a government should start bandying around estimates which are at the moment not very precise; by definition they're not very precise."

He appeared to hint there could be a rethink if the forecasts "become precise enough for us to believe that they merit being put out there".

However, a spokesman for the Liberal Democrat leader said: "He was referring to the fact that there are estimates around - for example from Migration Watch - which he has seen but which he does not think are robust.

"There are also government figures on the numbers currently in the UK and the percentage in the UK compared to other EU countries.

"However, the Government does not have forecast figures or estimates on the number of migrants that could arrive from Romania and Bulgaria.

"The point the DPM was making is that it is not credible to accurately forecast likely inflows from Romania and Bulgaria once restrictions are lifted, which is why he described figures being bandied about as guesstimates."

Shadow immigration minister Chris Bryant said: "David Cameron's Government is in a hopeless mess on estimates for the number of people coming from Bulgaria and Romania - contradicting each other on who knows what while at the same time refusing to come clean and publish the figures they've had.

"They should trust the public's common sense and publish the impact assessment immediately so that we can all decide for ourselves whether the plans in place are adequate.

"People are sick of governments making promises and politicians spouting warm words about immigration but doing nothing."